编程求两个一元多项式的乘积。



输入

　　输入数据为两行，分别表示两个一元多项式。每个一元多项式以指数递增的顺序输入多项式各项的系数（整数）、指数（整数）。



　　例如：1+2x+x2表示为：<1,0>,<2,1>,<1,2>,



输出

　　以指数递增的顺序输出乘积： <系数,指数>,<系数,指数>,<系数,指数>,



　　零多项式的输出格式为：<0,0>,-Programming seeking the product of two one-polynomial. Enter the input data for the two lines represent two unary polynomial. One dollar for each polynomial order of the exponential increase of the input polynomial coefficients (integer), index (integer). For example: 1+2 x+ x2 expressed as: " 1,0" , " 2,1" , " 1,2" , the output of the order of the exponential increase output of the product: " coefficient, index" , " coefficient, index" , "　coefficient, the index " , zero polynomial output format is:"　0,0 " ,